The present invention relates to a system and method for optically determining the dimensions and/or volumes of items.
For many applications, such as package delivery, it is desirable to quickly determine the dimensions of a container or item. In most cases, such as when boxes are being loaded onto a truck for transport and/or delivery, the dimensions of the containers or items are determined by a visual estimate or by measurement with a measuring tape before they are loaded.
Some systems employ a light curtain or photocell in combination with a conveyor to optically estimate the size of containers. In order for these systems to determine container sizes, a pre-measured item such as a ruler must be kept in the field of view so that the size of the container can be compared to the size of the pre-measured item in order to determine the container size, or optical techniques must be used to “build up” the dimensions of the container based on the known pixel size of the camera. These methods are either inconvenient (due to the use of external calibration) or error-prone (due to large errors caused by scaling up of pixels, for example).
In some particular applications, items may have the ability to transmit information by radio frequency identification (RFID) tags associated with each of the items. This is often a useful way to acquire information about items that are grouped together, such as on a pallet, without having to handle each individual item. However, in some cases, the RFID tags associated with the items do not all communicate successfully with an RFID tag reader being operated by handling personnel. In these situations, backup methods such as barcode reading and hand counting can be used to determine how many items are grouped together. However, these methods are labor intensive and inefficient.
An improved system for determining the size and number of items in various applications would be useful.